Fire arm casing and method  for manufacturing

ABSTRACT

This invention relates to a cartridge casing that has a substantially hemispherical end that integrally mates to a welded conforming base that stores a primer. One or more holes in the hemispherical end of the upper chamber aligns with a corresponding hole in the base having a lower pocket to allow primer gasses into the shell casing. The configuration of the base, in combination with upper chamber&#39;s distal end hemispherical concavity, removes from the prior art a nipple attachment to the upper chamber and sharp corners in the casing that allow for greater reliability in the integrity in the firing of the bullet, as well as the potential for a greater explosive effect due to a shorter passage to ignite the gun powder more uniformly by the primer source.

CROSS-REFERENCE TO RELATED APPLICATIONS

This non provisional patent application claims the priority benefit under 35 U.S.C. 120 of U.S. provisional patent application Ser. No. 62/947,013, filed on Dec. 12, 2019, the entire disclosure of which is hereby incorporated by reference.

FIELD OF THE INVENTION

This invention relates to a firearm cartridge and a method for its manufacturing.

BACKGROUND OF THE INVENTION

The present disclosure relates to a bullet cartridge used in firearms, such as hand guns and rifles. As is well-known in the art, an ammunition cartridge includes a generally metal (typically brass or steel) cylindrical case, with a bullet typically having a copper jacket and lead core, seated at one end of an upper chamber of the case, filled with gun powder and an explosive primer, located at the distal end of the cartridge, and contained in a lower chamber, which ignites the powder. The primer lower section generally has a pocket, where one or two vents or flash holes separate the primer lower section from the upper chamber containing the gun powder. The primer detonates upon impact of a firing pin from a firearm, causing hot gas to exit through the flash hole and into the upper chamber igniting the gun powder, which projects the bullet from the proximal end of the upper chamber.

The primer base of a centerfire cartridge must be able to withstand high pressures, which in turn give a bullet greater velocity and energy. One of the significant considerations in the design of the amount of priming explosive and its container is to insure the reliability and decrease the probability of misfire or dud cartridges.

As illustrated in FIG. 1, a conventional prior art bullet cartridge 10, has a proximal end, where the projectile or bullet 16 is installed into a case 14 having an upper chamber 20, which distal end attaches to a base 24 containing a primer lower pocket 11 having gunpowder 12 that consist of an explosive 18. The base 24 adapted to house the primer 12 has in its end facing the case 14, one or more relatively small diameter flash hole 28. When the primer 12 is struck by a firing pin (not shown), the primer 18 transforms into a gas. Early prior art cartridge cases are made from brass. Recent prior art casings, U.S. Pat. No. 10,260,847 ('847), are made from stainless steel with aluminum, steel or stainless steel bases. The base 24 may be manufactured from bar stock in a Swiss-style screw machine or a multi axis CNC lathe. The base 24 may also be cold formed from bar stock in a process similar to making nuts and bolts.

As shown in FIG. 1, FIG. 2, and FIG. 3A, (see, U.S. Pat. No. 10,260,847 ('847)) cartridge 10 has an upper chamber 20, contained in a metal tubing 22, which is either integral to the base (FIG. 1) or attaches to the base 24 (FIG. 2, FIG, 3A). The base 24 adapted to house the primer 12 and incorporate a flash hole 28 to allow the explosive gas to flow from the pocket 11 to the chamber 20. IN FIGS. 2 and 3A a light press fit secures the end of the nipple by rolling over the metal to form a rivet 9. When the '847 design, such as illustrated in FIG. 2, is fired, a pressure point 13 frequently causes a shell case 14 to deform or even rip open, thus preventing the spent shell to properly eject. The pressures are measured, which parenthetically is common knowledge in the industry. As an approximation, the sharp corner at pressure point 13 may cause fractures the base 24 at shell pressures exceeding 50,000 psi. The “wave” mentioned in the '847 patent flattens when the shell is fired causing the base of the casing to expand and in turn contact the rifle chamber preventing complete shell-base separation. Backup pressure data is available on line search “7.62 mm chamber pressure.” Links for chamber pressure can be found at: (1) http://www.leverguns.com/articles/saami_pressures.htm; and (2) http://kwk.us/pressures.html; and (3) http://www.lasc.us/SAAMIMaxPressure.htm.

When the prior art riveted design with the sharp corner 13 of the '847 patent is fired at high cycle rates, as for example, an automatic fire or machine gun, the ejection action of the gun bolt can rip the base 24 from the shell casing at the corner causing the gun to jam. What is needed is a design that eliminates the sharp corner 13 and uses the base 24 to support the shell casing at this high stress location to eliminate these types of malfunctions. In addition, what is needed is a design that improves the quality and manufacturability, reduces its cost and the overall weight of the shell, by removing unnecessary material.

SUMMARY OF THE INVENTION

This invention generally relates to a cartridge casing that has an upper chamber with a more or less hemispherical end that integrally mates to a conforming base, using a weld rather than the prior art nipple and rivet manner of securing the two main parts of the casing/base. The configuration of the base removes from the prior art the nipple and rivet. The welded design reduces the distance between the primer source and the powder charge as compared to the rivet design, allowing among other things a longer cylinder and hence greater volume upper chamber.

In one embodiment of the invention a cartridge casing includes: a substantially concave portion of an upper chamber bonded, by any reliable means, to a base to contain a lower pocket to achieve a minimal separation between the distal end of the upper chamber and the base with the lower pocket, which contains an explosive primer. An opening in the concave portion of the upper chamber aligns with a corresponding opening in the base's lower pocket to allow passage of the primer's gasses.

More particularly, in one embodiment, this invention relates to a cartridge casing that has a more or less hemispherical end that integrally mates to a welded conforming base with the lower pocket. In the present invention, welding the base creates a minimal separation between the upper chamber and the lower pocket containing the primer. Additionally the welding of the upper chamber to the base improves the reliability of the cartridge, by eliminating pressure points that may tear the upper chamber from the lower chamber.

A hole in the hemispherical distal end of the upper chamber aligns with a corresponding hole in the lower pocket to allow the primer gasses into the shell casing. The upper chamber's lower hemispherical concavity of the casing of the present invention also provides for an increase in the volume of the casing, which allows for a greater amount of gunpowder.

The increased reliability of the base against fracture or deformation, which occurs in part due to the impact of a faulty base unit, allows the cartridge to be reloaded and fired many more times than a prior art cartridge, and notably one utilizing a riveted technology, such as the '847 patent. The foregoing and other features and advantages will be fully appreciated from the more detail description and associated drawings which follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is prior art of a sectional view of a conventional prior art firearm cartridge.

FIG. 2 is prior art of a sectional view of a conventional prior art firearm cartridge

FIG. 3A is prior art sectional view of a base riveted to a shell casing, in conventional firearm cartridge

FIG. 3B is sectional view of a base welded to a shell casing in accordance with an embodiment of the invention

FIG. 4. is a plan view of a cartridge having base welded to a shell casing in accordance with an embodiment of the invention.

FIG. 5 is an expanded sectional view of a base welded to a shell casing in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description includes the best mode of carrying out the invention and is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is determined by reference to the claims. Each part or function is assigned, even if structurally identical to another part, a unique reference number wherever that part is shown in the drawing figures.

This disclosure details, as shown in FIG. 4, an improvement to a type of cartridge, referred to as a centerfire cartridge, where the primer is located in the center of the cartridge base, separate from the upper chamber 20, containing the gun powder, and constitutes a separate and replaceable component. With the exception of a few .17 caliber, .20 caliber, and .22 caliber pistol and rifle cartridges, small-bore shotgun cartridges, and antiques, almost all pistol, rifle and shotgun ammunition used today is centerfire.

In the preferred embodiment of the invention, FIG. 3B and FIG. 5 includes the shell case 14, a base 24, and a bullet 16 (FIG. 1). The primer contains an explosive 18 one non-limiting embodiment of the invention, includes the upper portion of a concave conformable base 24, which conformably mates to a substantially concave hemispherical end 25 b of the distal end of upper chamber 20. The union between the base 24 and the end 25 b is achieved via a weld 30, the top end of the base 24, which contacts the lower end of the upper chamber 20. Among other advantages to be discussed, one effect of this arrangement is that the weld 30 prevents the prior art pressure point 13 FIG. 3A, from manifesting , which as earlier stated frequently causes a shell case 14 to deform or even rip open, thus preventing the spent shell from properly ejecting.

The substantially hemispherical end 25 b of the upper chamber 20, which integrally mates via a weld 30, allows for a controlled amount of gun powder to be loaded, due a calculable and manufacturable volume in the formation of the concavity formed at the end 25 b.

The wave produced by the prior art FIG. 3A, 25 a, is not process controlled in its formation and therefore its geometric topology or surface varies from shell to shell. The concavity thus insures a greater degree of accuracy in the amount of gun powder used to fill the chamber 20.

Further to the incorporation of the substantially hemispherical end 25 b of an upper chamber 20 that integrally mates, via a weld 30, to attached base 24, is the reduction of the vertical dimension V_(d) of FIG. 3B, base 24 as compared to V_(d) of the prior are (see FIG. 3A, 24). The effect of reducing the vertical dimension V_(d) in the preferred embodiment of the invention is the minimization of the distance between the upper chamber 20 and the lower pocket 11 in base 24. In effect this allows the chamber 20 to be elongated by the difference between the distance X in FIG. 3A and the distance X in FIG. 3B. The result of this reduction in the X dimension is to allow a greater amount of gunpowder to be packed into the upper chamber as compared to the prior art. This aids in the power produced in the explosion of the gunpowder and hence the velocity of the bullet.

As mentioned the weld 30 also serves to add further reliability to the preferred embodiment of the invention by removing any requirement for a nipple attachment to the upper chamber 20, which results in sharp corners in the casing, causing unwanted pressure points (force/area of corners), during the ignition of the primer. Such additional extreme pressures result in damaging the upper chamber 20 and the base 24, such that a distortion or a tear, which may interfere with the ejection of the shell from the firearm.

It is recognized by those of ordinary skill in the art of firearms that the cartridge casing of the preferred embodiment of the invention has a greater explosive effect of a primer due to a shorter passage between the upper chamber and the base to ignite the gun powder

It is recognized by those of ordinary skill in the art of firearms that the cartridge casing produces a greater explosive effect of the gunpowder due to the upper chamber having an increased length due to the shorter passage between the upper chamber and the base.

Manufacturing a prior art casing from solid brass would requires the steps such as blanking, annealing, deep drawing and machining, all processes well known by those or ordinary skill in the art of metal manufacturing. Parts must be handled and or cleaned between each step. In the disclosed invention as in shown in FIG. 3B, and FIG. 5 the manufacturing process requires as few as 3 steps: machining/forming the base, drawing the case and welding the base to the casing. The prior art, shown in FIG. 2, having the riveted technology, adds considerably to the cost of manufacturing. In the disclosed invention drawing the case and welding the base to the case may be done at the same step, in one machine sequence, thus drastically reducing cost of manufacturing.

The welding processes mentioned previously are well developed by those of ordinary skill in the art of designing and fabricating metals using welding machinery as used throughout industry. Although many welding techniques may be employed, the manufacturing process in the preferred embodiment utilizes projection resistance welding, as shown in FIG. 5, which forms a weld 30, fusing the base 24 having a lower pocket 11 to the upper chamber 20. This weld process provides the fastest and most reliable production of the invented product.

However, it will be recognized that other bonding methods, including welding, brazing, soldering or adhesive processes may be employed without diminishing the integrity of bond of the invented product. In all instances, a weld schedule typically specifies electric current, pressure, timing, etc. dependent on a wide range of considerations, such as equipment availability and production rates.

One embodiment of the invention is a method for assembling a cartridge casing as in FIG. 3B and FIG. 5, which includes the steps of: (a) welding a hemispherical concave end 25 b of the upper chamber 20 to a conformable base 25; (b) establishing a minimal separation between the upper chamber 20 and a lower pocket 11; (c) containing an explosive primer in the lower pocket 11; (d) creating a hole in the hemispherical concave end of the upper chamber 20; (e) creating a hole in the lower pocket 11; (f) aligning the hole in the hemispherical concave end 25 b with the corresponding hole in the lower pocket 11; wherein the upper chamber 20 hemispherical concave end 25 b provides for: (a) increasing the volume of the casing, which stores gunpowder, (b) increasing reliability of the base against fracture or deformation, (c) allowing the cartridge to be reloaded and thus subsequently utilized.

While the foregoing invention has been described with reference to the above embodiments, additional modifications and changes can be made without departing from the spirit of the invention. Accordingly, such modifications and changes are considered to be within the scope of the appended claims. 

We claim:
 1. A cartridge casing comprising: a substantially concave portion of an upper chamber bonded to a base for minimal separation between the upper chamber, having a concavity at its distal end, and a lower pocket within a lower base, for containing an explosive primer, such that an opening in the concave portion of the upper chamber aligns with a corresponding opening in the lower base to allow passage of the primer's gasses, wherein the upper chamber concavity provides for increased reliability of the base against fracture or deformation.
 2. A cartridge casing comprising: a hemispherical concave distal end of an upper chamber integrally welded to a conformable base to establish a minimal separation between the upper chamber and a lower pocket within the base for contain an explosive primer, such that a hole in the hemispherical end of the upper chamber aligns with a corresponding hole to the lower pocket to allow the primer's gasses into the upper chamber.
 3. A method for assembling a cartridge casing comprising: (a) welding a hemispherical concave end of an upper chamber to a base conformable to the upper chamber; (b) establishing a minimal separation between the upper chamber and a lower pocket; (c) containing an explosive primer in the lower pocket; (d) creating a hole in the hemispherical concave end of the upper chamber; (e) creating a hole in the lower pocket; (f) aligning the hole in the hemispherical concave end with the corresponding hole in the lower pocket; wherein the upper chamber hemispherical concavity provides for: (1) increasing the volume of the casing, which stores gunpowder, (2) increasing reliability of the base against fracture or deformation, (3) allowing the cartridge to be reloaded.
 4. The cartridge casing of claim 1 wherein the a hemispherical concave end conforms to the base to establish a minimal separation between the upper chamber and the base.
 5. The cartridge casing of claim 1 wherein a hemispherical concave end is welded to a base to establish a minimal separation between the upper chamber and the base.
 6. The cartridge casing of claim 1 wherein an upper chamber hemispherical concavity provides for an increase in the volume of the casing to store gunpowder.
 7. The cartridge casing of claim 1 wherein an upper chamber hemispherical concavity allows the cartridge to be reloaded.
 8. The cartridge casing of claim 1 wherein a hemispherical concave end is welded to a base to allow the cartridge to be reloaded.
 9. The cartridge casing of claim 1 wherein a greater explosive effect of a primer to ignite the gun powder is due to a shorter passage between the upper chamber and the base.
 10. The cartridge casing of claim 1 wherein a greater explosive effect of the gunpowder is due to an increased amount of gunpowder in the upper chamber as a result of having an increased length due to the shorter passage between the upper chamber and the base. 